Electric bell



F. W. WOOD.

ELECTRIC BELL.

APPLICATION mm AUG-7. I9l9.

1,331,-1 34. Patented Feb. 17,1920.

INVENTQR J WM/ ATTORNEY %E I W UNITED STATES PATENT OFFICE.

FRANK W. WOOD, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO CHARLES CORY & SON,

ELECTRIC BELL.

Specification of Letters Patent.

Patented Feb. 17, 1920.

Application filed August 7, 1919. Serial No. 316,002.

To all whom it may concern:

Be it known that I, FRANK W. Wool), a citizen ofthe United States, residing at Montclair, in the county of Essex and State of New Jersey, have invented new and useful Improvements in Electric Bells, of which the following is a specification.

My invention relates to electric bells, and particularly to an improved construction and arrangement of the parts of bells of the vibrating armature type. v The elements of this well-known type of bell are substantially fixed, but the efiicienc; durability and reliability of different bell s vary greatly with different arrangement and construction of these elements. Particular difliculty is encountered under severe service conditions with the type of bell having armatures mounted on flexible connections.

My structure is of the type having a relatively long, heavy armature pivoted at one end and having a clapper directly connected to the armature. This type of construction is extremely durable and positive in action,

producing relatively heavy blows of theclapper and consequently a loud sound.

Furthermore, it avoids the unreliabilitycaused by distortion of the flexible element which carries the armature in a common type of construction. The weight of the armature and the clapper, however, is the cause of numerous difliculties in the provision of resilient means for opposing the action of the magnets and withdrawing the armature when the circuit is broken with iutficient rapidity to produce a practical The efliciency of the bell depends largely upon the speed with which the armature is vibrated and the sharp withdrawal of the clapper from contact with the bell, which is more diflicult when the clapper is not mounted on a flexible connection. I have provided improved resilient elements for moving the armature away from the magnets. Particularly, I have provided a resilient element operative on the extreme end ofthe armature, where its force will be most effective. I have furthermore constructed and arranged the element so as to increase its force as the armature approaches the magnets and is subject to increased magnetic force until the usual contact; connection is broken and the magnets are deenergized. The element then decreases its force exerted on the armature as the latter moves away from the magnets, until, as the maximum distance therefrom is approached, the element resists further movement and assists the magnets in reversing the direction of the armature as the contact is renewed and the magnets are again energized. Consequently my resilient means exerts its force particularly at the points where the armature is reversing its direction, thus greatly increasing'the speed of vibration and producing a particularly clear bell stroke.

It is practically necessary, in bells of this kind to provide an adjustable contact for suita' ly breaking the magnet circuit and also to provide means for adjusting the force exerted on the armature by the resilient means. As the bell structure is under constant vibration, which with heavy bells is considerably and sometimes long continued, a common source of trouble is the derangement of the adjusting means through vibration. 'I have provided simple and positive locking means for preventing such derangement.

I also haveconstructed and arranged the partsso that they may be assembled in a relatively small number of separate units, and these units may then be assembled to form the complete bell. This construction greatly facilitates both the initial assembly and repair of the parts. I have, furthermore, constructed the parts so that they may all be mounted upon asingle base, rendering them easily accessible and removable as a whole.

Where bells are used on circuits having relatively high voltage,'there is considerable difliculty from sparking between the contact points. I have provided a very simple and eflicient means of preventing sparking, said means consisting of a simple method of winding the magnets.

Further objects and advantages of my construction will be apparent from the following description taken in connection with the accompanying drawings, in which:

Figure 1 is a plan view, I

Fig. 2 is a side view from the left of Fig. 1, parts being shown in section,

Fig. 3 'is a fragmentary end view from the right of Fig. 1,

Fig. 4 is a wiring diagram illustrating the winding of the magnets to prevent sparking,

Fig. 5 is a fragmentary plan view, similar to Fig. 1, of a modified form, and

Fig. 6 is a plan view of one of the parts in Fig. 5.

I have shown my invention as applied to the type of bell in which the mechanism is ,mounted on a base plate 10. Magnets 11 are detachably mounted as by screws 12 upon standard 13, preferably consisting of a strip of angle iron mounted on base plate 10. Iron plates 14 are preferably held across the ends of the magnets by screws 12 and form,

with the adjacent portion of standard 13, a

convenient means for reducing' the reluctance of the magnetic circuits. Armature 15 is located adjacent the poles of magnets 11 and is mounted on rock shaft 16 near one end of the armature. The rock'shaft is journaled in suitable bearings, preferably in base plate 10 and in bearing plate 17, suitable collars 18 being mounted on rock shaft 16 at opposite sides of armature 15 to suitably position it relative to the base plate 10.

Armature 15 may be composed of a homogeneous bar of metal, but preferably consists of two plates 19 connected by suitable means, such as screws or rivets 20, the connection with rock shaft .16 being preferably made by clamping the shaft between plates 19.

I provide resilient means for normally holding the armature away from the poles of magnets 11, preferably consisting of leaf spring 21, one end of which is rigidly connected to armature -15 in any desired way as by clamping it between plates 19.

The middle portion of spring 21 is preferably'bowed as at 22 to produce the desired resiliency, and the other end thereof normally presses against an adjustable bearing, mounted on the side plate 23. This bearing preferably comprises a screw 24 threaded through side plate 23 and provided with means for holding it in adjustedposition, which may consist of clamping spring 25, through the ends of which adjusting screw 24 passes, the relatively strong expanding tendency of spring 25 tending to jam the portion of screw 24 which is threaded through side plate 23.

I provide a vibrator spring 26 mounted at one end on top plate 27, located lengthwise above armature 15 and having a downward extension 28 at its outer end, suitably apertured at 29 to receive therein a stud 30 of insulating material mounted in the end of armature 15. Aperture 29 is preferably elongated in the line of vibration of armature 15 for a purpose which will be hereinafter explained.

Contact arm 31 is mounted at one end on top plate 27 and is located above vibrator spring 26. Contact screw 32 is'threaded through the outer end of the contact arm and carries at its lower. end contact point 33 cooperating with contact point 34 connected to Vibrator spring 26 in any desired manner. The position of the contact between points 33 and 34 can be adjusted by rotating screw 32; and I provide means for firmly holding said screw in adjusted position. This means preferably consists of a clamping plate 35 mounted on the upper side of contact arm 31 as by clamping screw 36 passing loosely through plate 35 and threaded into arm 31, the plate being slightly spaced from the contact arm wit contact screw 32 threaded through the outer end of the plate. For convenience in construction I preferably form clamping plate '35 from a reversely bent extension of contact arm 31. I

I also providesuitable terminals, preferably including a terminal clip 37 connected to contact arm 31 as by screwing it on clamping plate 35, the clip being preferably provided with a loop 38 through which the lead wires'may be passed to keep them out of contact with the moving parts of the bell. The other terminal 39 is preferably carried by plate 40 of insulating material mounted on top plate 27, terminal 39 being suitablyconnected t'o magnet terminal plate 41 preferably mounted on the opposite side of plate 40 and adapted to receive one end of the circuit through the magnets, which are connected in series. The other end of the magnet circuit is electrically connected to vibrator sprin 26 as by connecting the end of the win ing to magnet terminal plate 42 mounted adjacent to and in contact with the vibrator spring.

While contact arm 31, terminal plate 40, and vibrator spring-26 may be mounted on top plate 27 in any desiredway, I prefer to mount them in superimposed relation with blocks of insulation 43 separating the vibrator spring 26 from plate 27 and 'contact arm 31, insulated bolts 44 passing which is detachably carried by base plate 10- as by bolts 46 through feet 47 on the lower ends of side plate 23 and top plate 27. Bell clapper 48 is connected to rock shaft 16 in any desired way, preferably forming an extension thereof. I have shown the clapper as located on the side of base plate 10 opposite to the operating mechanism and cooperating with bell 49 mounted on the same side of the base plate; but obviously the clapper may be formed as an extension of the opposite end of rock shaft 16 and the bell may be mounted above and inclosing the operating mechanism, in accordance with a standard type of construction. Other general arrangements of the clapper bell and supports for the operating mechanism are obviously possible.

Contact point 34 may either be mounted directly on vibrator spring 26, or in the form illustrated in Fig. 5, it may be carried by the outer end of auxiliary vibrator spring 1 50, the inner end ofwhich is attached to vibrator spring 26 in any desired way, as

.by rivet 51 a projecting toe 52 on the inner end of auxiliary vibrator spring 50 extending through a suitable aperture in vibrator spring 26 to prevent rotation of auxiliary spring 50 about the rivet. In this modified form aperture 29 is not elongated, being merely of sufiicient size to permit free play of stud 30, as auxiliary spring 50 performs a function similar to that of the elongated aperture, as will be hereinafter explained.

For use with low voltage circuits the magnet windings may be of the usual primary type; but for use with high voltage circuits I provide means for preventing sparking at the contacts, this means preferably consisting of suitable windings for magnets 11. I prefer to form these windings by introducing in each magnet a secondary winding 53 wound in the same direction as primary winding 54, the ends of each secondary winding being directly connected adjacent the magnet to short-circuit the windmg. I

In operation, the energizing of magnets 11 pulls armature 15 downwardly against the adjustable tension of spring 21, until stud 30 comes in contact with the lower end of aperture 29. Vibrator spring 26 thereupon adds its force to spring 21 to check the movement of the armature toward magnets 11, the resiliency of spring 26 permitting the armature to travel downward a slight distance after stud 30 has contacted with the bottom of aperture 29 befo e contact 34 is separated from contact 33, thus producing a more or less gradual slowing down of the motion of the armature prior to the release of the magnetic force exerted thereon. Upon the breaking of the contact, the armature flies upward under the impulse of spring 21 with the initial assistance of spring 26, the contact being immediately restored, so that the magnetic attraction arrests the armature and again moves it down- -tion of adjusting screw 21, the force of spring 25 being insufficient to prevent the use of an ordinary screw driver, but being adequate to clamp the screw firmly in adjusted position. Contact 33 is adjusted by rotation of screw 32, which is then clamped in adjusted position by tightening screw 36, jamming "screw at the points where it is threaded through clamping plate 35 and contact arm 31 and affording a very strong, positive and easily operated means for preventingthe derangement of this adjustment, which forms a very common source of trouble in bells of this kind.

The operation of the modification shown in Fig. 5 is slightly different, though the same in principle and effect. In this form the motion of the armature toward the magnets is constantly opposed by vibrator spring 26, but auxiliary spring 50 tends to push the vibrator spring downwardly with a force decreasing with the downward motion of spring 26 until it reaches zero; and the further motion of spring 26 separates the .contact points and permits the armature to move upwardly. The action of auxiliary spring 50 against the pull of vibrator spring 26 on the armature decreases as the armature approaches the magnets, thus assisting to produce a quick reversal of the motionof the armature. In a similar way the increased opposition between spring 50 and vibrator spring 26 as the armature moves upward produces increased resistance to such upward motion, tending to facilitate the rapid reversal of the motion of the armature as the magnets are again energized.

The secondary coils .53 effectually check sparking of the-contacts. This sparking is caused by the surge of current produced by the self-induction of the primary circuit when the contact is broken; and the current induced in the secondary winding by the breaking of the primary circuit and the consequent current drop in the primary winding induces, in turn, a: current in the primary winding in a direction opposite to that of the self-induced current, thereby .tending to nullify the force of the latter,

and to prevent the sparking by eliminating its cause. This is believed to be thetheory of operation of the construction described, but regardless of the correct theory of operation, my construction in'practice tends substantially to prevent sparking. I

It will be observed that I'have so arranged and constructed the operative parts that they include practically three separate units; namely, the magnets, the armature and the vibrator structure. The latter is preferably mounted entirely on yoke 45, the connections with the armature being such that the entire structure may be entirely removed by disconnection of yoke 45 from base plate 10, since vibrator spring 26 may be slipped ofi of stud 30 and only contact engagement between spring 21 and side plate 23 is provided. Moreover, I have preferably mounted the entire structure on a single base plate 10,'thus facilitating the removal thereof in one unit, preferably constructed so that the mounting of the bell need not be disturbed.

The construction is simple and very strong, the weight of the vibrating parts, necessary to insure durability, being compensated by the special spring structure, as vibrator spring 26 aids in the reversal of direction of the armature in such a way as to provide a very rapid vibration in spite of the mass of the armature which insures powerful magnetic attraction thereof by the magnets. The only parts which can possibly be deranged by vibration are the adjusting screws, which are strongly clamped in position, all other connections being simple and strong, producing a 'bell, which, in practice, has shown surprising results as to durability and reliability.

While I have described a preferred form of my invention and some modifications, it will be apparent that many other changes may be made therein; and I do not consider my invention to be limited to the specific disclosure, but consider it to be commensurate with the scope of my inventive idea as disclosed in the specification and covered in the claims.

I claim:

1. In electro-mechanical apparatus for producing vibrations, a magnet, an armature pivoted adjacent one end, a leaf spring mounted independently of said armature and having a down-turned end engaging the end of the armature, operative to retract the armature from the magnet, and means connected to the leaf spring for intermittently interrupting the magnet circuit, operative to vibrate the armature.

2. In electro-mechanical apparatus for producing vibrations, a magnet, an armature pivoted adjacent one end, a leaf spring having a down-turned end with an aperture in said end, a stud on the end of the armature passing through the aperture to engage the spring with the armature, and means connected to the leaf spring for intermittently interrupting the magnet circuit, operative to vibrate the armature.

3. In electro-mechanical apparatus for producing vibrations, a magnet, an armature pivoted adjacent one end, a vibrator spring lying parallel to the armature and insulated therefrom, mounted at one end adjacent the armaturepivot and having an opposite end engaging the oscillating end'of the armature; a contact element connected to the spring, and a coiiperating contact mounted adjacent the spring on the side opposite to the magnet, the construction being such that the alternate operation of the spring and the magnet intermittently interrupts the magnet circuit and vibrates the armature.

4.. In electro-mechanical apparatus for producing vibrations, a magnet, an armature pivoted adjacent one end, a support, a vibra tor spring insulated from and lying parallel to the armature on the side .opposite the magnet and mounted at one end on said sup port unconnected to and independent of the mounting of said armature, having its opposite end engaged with the oscilating end of the armature, a contact arm mounted on said support insulated from the vibrator spring and lying parallel thereto on the side opposite the magnet, a contact carried by said arm and a coiiperating contact connected to the spring, the construction being such that the alternate operation of the spring and the magnet intermittently interrupts the magnet circuit and vibrates the armature.

5. In electro-mechanical apparatus for producing vibrations, an armature, means for vibrating said armature including a magnet and means for intermittently interrupting the magnet circuit, said interrupting means including apair of complementary contacts, an element carrying one of said contacts, a support for the element having its outer end reversely bent and lying parallel to and slightly spaced from the support, the element being threaded through the reversely bent end and the support, and means for drawing the end and the support together to clamp the element in position.

6. In electro-mechanical apparatus for producing vibrations, a magnet, an armature pivoted adjacent one end, a spring element attached to the armature at said end to retract it from the magnet, means for adj usting said resilient element, and means for intermittently energizing the magnet to vibrate the armature.

7 In electro-mechanical apparatus for producing vibrations, a magnet, an armature pivoted adjacent one end, resilient means engaging the armature at the pivoted end to retract it from the magnet, independent resilient means engaging the opposite end of the armature, and means connected to said independent means operative to intermittently interrupt the magnet circuit, the construction being such that the alternate operation of the resilient elements and the magnet vibrates the armature.

8. In electro-mechanical apparatus for producing vibrations, a magnet, an armature pivoted adjacent one end, a stud carried by the opposite end of the armature, resilient retracting means detachably engaging the stud and insulated from the armature, and means for intermittently energizing the magnet circuit for vibrating the armature. 9. In electro-mechanical apparatus for producing vibrations, a magnet, an armature consisting of two plates fastened together, a pivot for the armature clamped between the plates, resilient means for retracting the armature and means for intermittently energizing the magnet to vibrate the armature.

Y 10. In electro-mechanical apparatus for producing vibrations, a magnet, an armature consisting of two plates fastened together, a pivot for the armature clamped between the plates, a spring clamped be tween said plates operative to retract the armature, and means for intermittently energizing the magnet to vibrate the armature. 11. In electro-mechanical apparatus for producing Vibrations, a base, a magnet mounted on the base, an integral support detachably mounted on the base, an armature pivoted in the base, and means carried entirely by said support for retracting the armature and for intermittently energizing the magnets to vibrate the armature.

12. In electro-mechanical apparatus for producing vibrations, a base, a magnet mounted on the base, an integral support detachably mounted on the base, an armature pivoted in the base, a spring element mounted on the su port and engaging the oscillating end of t e armature to retract it from the magnet, a contact carrier, a contact point supported thereby, a cooperating contact point connected to the spring, said contact points being connected in circuit with the magnet, the'construction being such that the alternate operation of the spring and magnet operates to vibrate the armature and to interrupt the magnet circuit intermittently.

13. In electro-mechanical apparatus for producing vibrations, a base, a magnet mounted on the base, an integral support detachably mounted on the base, an armature pivoted in the base, a spring element mounted on the support and engaging the oscillating end of the armature to retract it from the magnet, a resilient element carried by the armature, means carried by the support for adjusting the tension of the resilient element, a contact carrier, a contact point supported thereby, a cooperating contact point connected to the spring, said contact points being connected in circuit with the magnet, the construction being such that the alternate operation of the spring and magnet operates to vibrate the armature and to interrupt the magnet circuit intermittently.

In testimony whereof I have hereunto set my hand. 1

FRANK W. WOOD. 

